diff --git a/xbps-src b/xbps-src
index 1c83708c8da..819aa106e9e 100755
--- a/xbps-src
+++ b/xbps-src
@@ -217,7 +217,8 @@ $(print_cross_targets)
 -t  Create a temporary masterdir to not pollute the current one. Note that
     the existing masterdir must be fully populated with binary-bootstrap first.
     Once the target has finished, this temporary masterdir will be removed.
-    This flag requires xbps-uchroot(1).
+    This flag requires xbps-uchroot(1), and won't work on filesystems that don't
+    support overlayfs.
 
 -V  Print version of xbps, then exit.